Liquid crystal displays (LCDs) have been widely used in technique field of display. In order to drive liquid crystals to rotate so as to achieve function of display, the LCD comprises a plurality of drive circuits such as gate drive circuit and source drive circuit. Drive circuits are generally manufactured on a printed circuit board (PCB). PCB refers to a circuit board provided with only wirings but no components, whereas a circuit board on which both wirings and components are disposed is referred to as a printed circuit board assembly (PCB′A).